Failure of the Thrust Reverser Isolation Valve (Shut-Off Valve in the closed position) on the Engine 1

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1. Possible Causes
· VALVE-THRUST REVERSER HYDRAULIC ISOLATION, ENG1 (50EG1)
· RELAY-THRUST REVERSER LOCKING POWER, ENG1 (2EG1)
· C/B-ENG1/REV/LOCK ( 1EG1 )
· wiring
· C/B-ENGINE/ENG1/OIL/PRESS/AND REV SNSR/CHAN A ( 2EN1 )
· STATIC RELAY-THRUST REVERSER LOCKING CTL, ENG1 (3EG1)
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
78-30-00-810-835-A Failure of the Thrust Reverser Hydraulic Control Unit on Engine 1
Ref. AMM 78-31-00-710-041 Operational Test of the Thrust Reverser System with the CFDS
Ref. ASM 78-37-01
Ref. AMM 78-37-51-000-010 Removal of the Thrust Reverser Hydraulic Isolation Valve
Ref. AMM 78-37-51-400-010 Installation of the Thrust Reverser Hydraulic Isolation Valve
3. Fault Confirmation
Subtask 78-37-00-865-054-A
A. Make sure that this(these) circuit breaker(s) is(are) closed:
PANEL DESIGNATION FIN LOCATION
49VU FLIGHT CONTROLS/SEC1/NORM/SPLY 21CE1 B08
105VU FLT CTL/SEC1/STBY SPLY 22CE B01
121VU ENG1/REV/LOCK 1EG1 N44
121VU ENGINE/ENG1/OIL/PRESS/AND REV
SNSR/CHAN A
2EN1 N40
121VU FLIGHT CONTROLS/SEC2/SPLY 21CE2 Q18
Subtask 78-37-00-710-058-A
B. Test
(1) Do the operational test of the thrust reverser system (1A and 1B) Ref. AMM 78-31-00-710-041 .
4. Fault Isolation
Subtask 78-37-00-810-054-A
A. If the test gives the maintenance message:
ADD REV LK SENS/HC 1
· do a check of the hydraulic line connections for leaks
· make sure that the plug connectors of the HCU and the thrust reverser hydraulic isolation valve, are
correctly connected.
(1) If you find that all is normal:
· do a check to listen for the operation of the thrust reverser hydraulic isolation valve during the
operational test of the thrust reverser Ref. AMM 78-31-00-710-041 .
NOTE: Two persons are necessary for this check:
- one in the cockpit to operate the thrust reverser control lever
- one at the HCU to listen for the related click.
(a) If the isolation valve operation is satisfactory and the reverser does not open:
· do the trouble shooting of the failure of the HCU (Ref. TSM 78-30-00-810-835) .
(b) If the isolation valve operation is not satisfactory:
· disconnect the electrical connector from the isolation valve
· move the ENG1 throttle control lever to the REV position
· move the ENG2 throttle control lever to the IDLE position.
NOTE: Make sure that you are not in the EEC menu mode.
· do a check for 115VAC at the connector between pin 1 and pin 2 from the harness side.
1 If there is 115VAC:
· replace the VALVE-THRUST REVERSER HYDRAULIC ISOLATION, ENG1 (50EG1)
Ref. AMM 78-37-51-000-010 and Ref. AMM 78-37-51-400-010 .
2 If there is no 115VAC:
a Move the ENG1 throttle control lever in the idle position.
b Disconnect the plug connector 752VC1 at the pylon interface.
c Move the ENG1 throttle control lever to the REV position.
d At the pylon interface, do a check for 115VAC at the connector 752VC1 between pin 1
and pin 2.
. If there is 115VAC:
· repair the wiring between the connector 752VC1 and the isolation valve (50EG1).
. If there is no 115VAC:
· do a check for 115VAC between pin 1 of the connector 752VC1 and an other ground
point.
. If there is 115VAC:
· repair the wiring between the pin 2 of the connector 752VC1 and the ground.
. If there is no 115VAC:
· do a check of the wiring between the connector 752VC1 pin 1 and the engine 1 thrust
reverser locking power relay (2EG1) pin A2 Ref. ASM 78-37-01.
. If there is no continuity:
· repair it.
. If there is continuity:
· do a check for 115VAC on the pin A/A1 of the engine 1 thrust reverser locking power
relay (2EG1).
. If there is 115VAC:
· replace the RELAY-THRUST REVERSER LOCKING POWER, ENG1 (2EG1) .
. If there is no 115VAC:
· do a check for 115VAC at the pin A/B1 of the relay (2EG1).
. If there is no 115VAC at pin A/B1:
· do a check and repair if necessary the wiring between the circuit breaker (1EG1) and
the relay (2EG1) pin A/B1 Ref. ASM 78-37-01
· if the wiring is correct, replace the C/B-ENG1/REV/LOCK ( 1EG1 ) .
. If there is 115VAC at pin A/B1:
· do a check for 115VAC at the pin A/B2.
. If there is 115VAC at pin A/B2:
· repair the wiring between the pins A/B2 and A/1.
. If there is no 115VAC at pin A/B2:
· do a check for 28VDC on the pin A/X1 of the engine 1 thrust reverser locking power
relay (2EG1) Ref. ASM 78-37-01.
. If there 28VDC at pin A/X1:
· do a check for a ground signal at the relay (2EG1) pin A/X2 and repair as necessary.
* If there is a ground signal:
· replace the RELAY-THRUST REVERSER LOCKING POWER, ENG1 (2EG1) .
* If there is no ground signal:
· repair the wiring .
. If there is no 28VDC at pin A/X1:
· do a check for 28VDC on pin A/A of the engine 1 thrust reverser locking control static
relay (3EG1).
. If there is 28VDC:
· repair the wiring between the relays (2EG1) and (3EG1).
. If there is no 28VDC:
· do a check for 28VDC on the pin A/X of the relay (3EG1).
* If there is no 28VDC at the pin A/X
· do a check and repair as necessary, the wiring between the relay (3EG1) pin A/X and
the circuit breaker (2EN1)
· if the wiring is correct replace the C/B-ENGINE/ENG1/OIL/PRESS/AND REV SNSR/
CHAN A ( 2EN1 ) .
* If there is 28VDC at the pin A/X:
· do a check for a ground signal on the pin A/Z of the engine 1 thrust reverser locking
control static relay (3EG1).
* If there is no ground signal:
· repair the wiring .
* If there is a ground signal:
· do a check for 28VDC on the pin A/1 of the relay (3EG1).
* If there is 28VDC:
· replace the STATIC RELAY-THRUST REVERSER LOCKING CTL, ENG1 (3EG1) .
* If there is no 28VDC:
· do a check and repair as necessary the wiring between the terminal block 2264VT
and the relay (3EG1).
* If the check is correct:
· refer to the Fault Symptoms List of the Chapter 27
· do a check and repair as necessary the wiring between the SEC-1 (1CE1)/SEC-2
(1CE2) and the terminal block 2264VT.
Subtask 78-37-00-710-059-A
B. Do the test given in Para. 3. [Rev.6 from Feb 2017] 2026.04.04 04:38:20 UTC